Spark-plug.



W. S. WITTER.

SPARK PLUG.

AlfPLIGATIQH FILED 210 7.20, 1911.

m'ygggaa Patented Nov. @1913.

licr i.

" n srarus WILLIAM S. WITTER OF TOLEDO, IOWA.

' I I creamer-Jus To all wkom 2'3 may concern: A

Be it known that 1, WILLIAM S. Wrrmn, a citizen of the United States, residing at Toledo, in the county of Tania and State of liowa, have invented certain new and useful Improvements in Spark-Plugs, of which the following is a specification, reference being had to the accompanying drawings.

This invention comprehends certain new and useful improvements in spark plugs of the type that are designed to produce two sparks in rapid succession at each operation of the plug, and the invention has for its primary object a simple, durable and eflicient construction of device of this character, the parts of which are so arranged that the plug will possess the characteristic of serviceability. to a high degree and not be liable to become clogged up and short circuited.

With this and other objects in view, as will more fully appear as the description proceeds, the invention consists in certain constructions, arrangements and combinations of the parts that I shall hereinafter fully describe and claim. i

For a full understanding of the invention, reference is to be had to the following description and accompanying drawing, in which,

Figure 1 is a side elevation of a spark plug embodying the improvements of my in vention. Fig. 2 is a sectional view thereof with, parts in side elevation. Fig. 3 is a detail perspective view of an intermediate electrode employed. Fig. 4 is a fragmentary inverted perspective view illustrating a modification, and, Fig. 5 is a bottom plan view of the said intermediate electrode.

Corresponding and like parts are referred to in the following description and designated in the accompanying drawir g by like reference characters.

Referring to the drawing, the numeral 1 designates astem which is formed at one end with a circular'head 2 terminating in a somewhat angularly projecting terminal point or electrode 3. On the opposite end of the stem 1 are the usual binding nuts 4; and 5 for the conducting wire. The stem 1 extends through and is mounted in a core 6 of in- 'sulat-ing substance, said core being formed intermediate of its ends with an exterior flange or bead 7, whereby it may be detach ably held in the casing 8 which is extenorly Specification of letters rarest.

Patented Nov. 4, 1912, Application filed November 20, 1911-. Serial No. 861,250.

* threaded at one end in the custommanner, whereby the plug may be easily attached to the cylinder of an internal cornbustion engine.

The core 6 is provided with a detachable clamping section 10 which is formed with a tubular neck 11 designed for reception in a socket 12 formed in one end of the core, as clearly illustrated in Fig. 2, the outer or lower end of the section 10 abutting against the head 2 of the electrode, whereby, by tightening up the not 5, a clamping action may be produced between the clamping section 10 at the shoulder where the neck 11 v is formed and the adjoining end of the core 6 which projects through andbeyond the inner or lower end of the shell 8'.

An intermediate electrode 9 such as that illustrated in detail in Figs. 3 and 5, is de signed to be detachably held against the end of the core by the clamping action of the head 2 and detachablesection 10 of mica. In thatembodimentof this device which is illustrated in Figs. 3 and 5, the said electrode 9- is formed with a collar which is formed with a centrally disposed opening 13, whereby it may be slipped over and upon the neck 11 and be clamped securely between the end of the core 6 and the detachable or clamping section 10 thereof. The electrode 9 is formed with two diverging and preferably downwardly extending terminal point-s 14C and 15, the point 14 being disposed in closely spaced relation to the point 3 and the point 15 being similarly disposed with reference to the grounded electrode 16 which is secured to the inner or lower end of the shell 8 and which is preferably forked atits free extremity, as clearly illustrated in Figs. 1 and 2. It is to be particularly noted that the collar of the intermediate electrode 9 is exposed below the lower end of the shell 8, there being a direct'air gap bet-ween said collar and the grounded electrode 16, whereby, even should the point 15 and the points of the electrode 16 become connected by soot or the like, there will still be a gap between the collar 9 and the electrode 16. Similarly, it is to be noted that the head2 is exposed'below the end of the core so that should the points 3 and 14: become short cir'cuited, there will still be a gap between theprimary electrode, and the spark will leak from the head 2 to the intermediate'electrode 9. Preferabl-y, theshell 8 is interiorly beveled in its lower end so that the relative distance between the intermediateelectrode 9 and the shell will be increased.

In the construction shown in Fig. 4;, the intermediate electrode consists of a circular piece of material that is tapering in shape, as shown, the lower end thereof coming close to the contact point 3. In this embodiment of the device, the contact points may be readily changed without removing the intermediate electrode from the plug. By simply turning saidelectrode, new points of service may be'brought into registry with the contact points of the shell and primary electrode or contact point 3, respectively. It

is to be noted that the contact point 3 projects away from the electrode 16, whereby to increase the positive action of the device in producing two distinct sparks in rapid succession.

What I claim is l. A spark plug, including a shell, a core mounted in said shell and projecting below the same, an intermediate electrode provided with a collar, a detachable clamping section secured to the end of the core and clamping the collar of said intermediate electrode against the end of the core and in an exposed position below the lower end of the shell, a stem mounted in the core and extending therethroughand provided with a head. ex-

posed below the lower end of the core, and an electrode secured to the shell and extending below and-in spaced relation to the collar of the intermediate electrode and said inter-'. mediate electrode being provided with diverging points, one of which extends close to and in spaced relation to the second named electrode, the stem being provided with a point extending away from the second named electrode and arranged in closelv spaced'relation to the other point of the intermediate electrode.

2. A spark plug, including a shell, a core mounted in said shell and projecting below the same, an intermediate electrode providenwith a collar, a detachable clamping section secured to the end of the core and clamping the'collar of said intermediate electrode against the end of the core and in an exposed position below the lower end of I the shell, a stem mounted in the core and extending therethrough and provided with a head exposed below the lower end of the core, and an electrode secured to the shell and extending below and in spaced relation to the collar of the intermediate electrode and said intermediate electrode being provided with diverging points, one of which extends close to and in spaced relation to WILLIAM S. WITTER.

Witnesses: I

F. C. MCCLASKEY, RUTH Rnms. 

